Multiphase control method of converter

Abstract

The invention discloses a multi-phase interleaving control method of a converter, and relates to the field of switching converters. The multi-phase converter is used for solving the problem that the efficiency of the multi-phase converter cannot be optimized and improved all the time in a double-phase load, a three-phase load and even a multi-phase load due to the fact that multiple switching tubes work. According to the method, phase adding work can be correspondingly controlled and switched along with output load increasing until full-phase work is achieved. Through the control method provided by the invention, only single-phase working is realized in light load, so that the working quantity of the switching tubes is reduced in a low-load working condition, the switching tubes are correspondingly switched to multiple phases in heavy load, and the switching loss can be remarkably reduced. Meanwhile, the inductive current is stable in the phase switching process, the current of the working phase does not suddenly change in a step mode, large disturbance of the output voltage is avoided, the switching control process is stable, and the reliability is high.

Description

A multiphase control method for a converter Technical Field

[0001] This application relates to the field of switching converter technology, and specifically to a multiphase control method for a converter. Background Technology

[0002] With the rapid development of modern high-performance computing devices (such as servers, workstations, communication equipment, and high-end graphics cards), their core processors (CPUs, GPUs, ASICs) place extremely stringent demands on the dynamic response, current output capability, and conversion efficiency of power supplies. To meet the requirements of high current, low voltage, and fast transient response, multi-phase interleaved parallel buck converters have become the mainstream power supply architecture in the industry. This architecture connects multiple identical buck circuit units (i.e., "phases") in parallel, with their drive signals staggered by a certain phase (e.g., 360° / N in an N-phase converter), thereby significantly reducing output current ripple, reducing the size of filter components, and improving the dynamic response speed of the system.

[0003] However, traditional fixed multiphase operation exhibits significant efficiency deficiencies in wide load range applications, especially under light or medium load conditions: Light load switching losses dominate efficiency degradation. Under light load conditions, although the total output current is small, all phases remain in a switching state. At this point, the switching losses of each phase's transistors become extremely significant in the total losses. These switching losses are proportional to the switching frequency and do not decrease linearly with decreasing current under light load conditions, leading to a substantial drop in overall system efficiency under light load.

[0004] Weighted efficiency standards require that current major global energy efficiency standards, such as 80 PLUS (servers / data centers), Energy Star, and the European Union's Code of Conduct (CoC), not only assess the peak efficiency of power supplies but also emphasize their weighted average efficiency at typical load points (such as 10%, 20%, 50%, and 100% load). This means that optimizing efficiency under light and medium loads is crucial for improving a product's overall energy efficiency rating and market competitiveness. Summary of the Invention

[0005] This application aims to overcome the problem of low efficiency of existing fixed multiphase operating modes under light and medium loads, and provides a two-phase, three-phase and multiphase control method for converters, which effectively improves the efficiency of multiphase interleaved topologies under low loads.

[0006] In one embodiment, this application discloses an interleaving control method for a two-phase switching converter. The control method includes: a first load threshold; a load equal to or lower than the first load threshold is considered a low load, and a load higher than the first load threshold is considered a high load; under low load conditions, only one phase operates, the operating phase being the first phase, and the non-operating phase being the second phase; the first phase has a predetermined drive-on time and duty cycle; under high load conditions, the first phase and the second phase operate simultaneously; a switching occurs when the load transitions from the low load to the high load; the switching is as follows: the first phase continues to operate, its drive transistor is turned on, and the drive-on time and duty cycle of the first phase are reduced to half of that under single-phase operation; after the single-phase duty cycle of the first phase ends, the drive transistor of the second phase is turned on, its drive phase being offset by 180° from the drive phase of the first phase, and the drive-on time and duty cycle of the second phase are reduced to half of that under single-phase operation; both phases then begin operating, thereby completing the switching from the low load to the high load.

[0007] In some embodiments, this application discloses an interleaved control method for a three-phase switching converter. The control method includes: a first load threshold and a second load threshold; a first load occurs when the load is equal to or lower than the first load threshold; a second load occurs when the load is between the first and second load thresholds; and a third load occurs when the load is higher than the second load threshold. During the first load, only one phase operates, with the first phase operating and the second and third phases not operating. The first phase has a predetermined drive-on time and duty cycle. A first switch occurs when transitioning from the first load to the second load. During this first switch, the first phase continues to operate, driven by its active transistor, reducing the drive-on time and duty cycle of the first phase to half that of single-phase operation. After the single-phase duty cycle of the first phase ends, the active transistor of the second phase is driven on, with its drive phase offset by 180° from the drive phase of the first phase, further reducing the drive-on time and duty cycle of the second phase. The load is reduced to half the operating time of a single phase, with both phases starting to operate, thus completing the switch from the first load to the second load. A second switch occurs when transitioning from the second load to the third load. In this second switch, the first phase continues to operate, its drive transistor is turned on, and the drive time and operating cycle of the first phase are reduced to two-thirds of the first or second phase's operating time when both phases are operating. After the two-phase operating cycle ends, the drive transistor of the third phase is turned on, its drive phase offset by 120° from the first phase's drive phase, and the drive time and operating cycle of the third phase are reduced to two-thirds of the first or second phase's operating time when both phases are operating. After the two-phase operating cycle ends, the drive transistor of the second phase is turned on after a predetermined time, its drive phase offset by 240° from the first phase's drive phase, and the drive time and operating cycle of the second phase are reduced to two-thirds of the first or second phase's operating time when both phases are operating. All three phases then start operating, thus completing the switch from the second load to the third load.

[0008] In some solutions, an interleaving control method for a multiphase switching converter includes: setting several load thresholds and defining load types according to the threshold range of the working load; when the load operates in a first load range, it is a first load; when the load operates in a second load range, it is a second load; when the load operates in the (n-1)th load range, it is the (n-1)th load; when the load operates in the nth load range, it is the nth load, where n > 3; when the first load is in operation, only one phase operates, the operating phase is the first phase, and the phases not operating are the second phase, the (n-1)th phase, and the nth phase, the first phase has a predetermined drive-on time and duty cycle; when switching to the nth load, the switch is that the first phase continues to operate, and the active transistors of each phase are driven to operate in staggered phases according to a predetermined time, wherein the drive-on time and duty cycle of each phase are reduced to 1 / n of the total drive-on time and duty cycle of the original single-phase operation, and all n phases start operating, thereby completing the multiphase switching.

[0009] The beneficial effects of this application are: This application can not only effectively improve the efficiency of multiphase interleaved topology under low load, but also stabilize the inductor current during two-phase phase switching, and the current of the working phase will not suddenly change stepwise, resulting in large disturbances in the output voltage. Attached Figure Description

[0010] Figure 1 shows the control waveform diagram of bidirectional interleaved topology control switching from single-phase to two-phase control in some embodiments of this application; Figure 2 shows the control waveform diagram of tridirectional interleaved topology control switching from single-phase to two-phase and from two-phase to three-phase control in some embodiments of this application.

[0011] Figure 3 is a schematic diagram comparing the overall efficiency of the product before and after applying the control method of this application in some embodiments of this application. Detailed Implementation

[0012] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application. Similarly, the following examples are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, methods, processes, or other characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0014] In some implementations, referring to Figure 1, this application provides a two-phase control method for a converter. The control strategy, which shuts off one phase and allows only one phase to operate during low output load operation, includes the first phase's active transistor driving Vg1 and its first-phase energy storage inductor L1, and the second phase's active transistor driving Vg2 and its second-phase energy storage inductor L2. The control method includes: setting a first load threshold; when the load is equal to or lower than the first load threshold, it is considered a low load; when the load is higher than the first load threshold, it is considered a high load; during low load operation, only one phase operates, with the operating phase being the first phase and the non-operating phase being the second phase; the first phase has a predetermined drive-on time and duty cycle; during high load operation, both the first and second phases operate simultaneously.

[0015] In this embodiment, when operating below half load, it is considered a low load, and only the first phase is operational. As shown in Figure 1, when the active transistor of the first phase drives Vg1 to output a high level, the energy storage inductor L1 of the first phase is energized, and the current increases linearly; when the active transistor of the first phase drives Vg1 to output a low level, the energy storage inductor L1 of the first phase is demagnetized, and the current decreases linearly.

[0016] When operating at half load or above, it is considered a high load, and both phases operate simultaneously. As shown in Figure 1, the first phase's active transistor drives Vg1 to output a high level, energizing the first phase's energy storage inductor L1, and the current increases linearly. The second phase's active transistor drives Vg2 to output a high level, 180° out of phase with the first phase, energizing the second phase's energy storage inductor L2, and the current increases linearly. The first phase's active transistor drives Vg1, and the second phase's active transistor drives Vg2 to output a low level, demagnetizing the first phase's energy storage inductor L1 and the second phase's energy storage inductor L2, and the current decreases linearly.

[0017] When the load changes from low to high, after the single-phase duty cycle of the low-load phase ends, the first phase resumes operation. The first phase's active transistor drives Vg1 to output a high level for half the duration of the single-phase drive's on-time, and the first phase's cycle also becomes half the single-phase duty cycle. After the first phase's single-phase duty cycle ends, the second phase's active transistor drives Vg2 to output a high level 180° out of phase with the first phase, also for half the duration of the single-phase drive's on-time, and the second phase's cycle also becomes half the single-phase duty cycle. At this point, both phases begin operating, thus completing the switch from low to high load.

[0018] In this embodiment, the transition from low load to high load and the switching from single-phase to dual-phase occur without changing the total conduction time. Each phase operates at half the single-phase conduction time, and the frequency is doubled, ensuring that the total transmitted energy remains constant and the output is stable. At the same time, the switching occurs at the beginning of a new cycle, preventing sudden changes in the current of the existing energy storage inductor and thus protecting the system's reliability.

[0019] As an example, as shown in Figure 3, the efficiency of a two-phase 2500W product can reach 98.2% when operating with a 35% output load and can be improved to 99.0% when operating with only a single phase.

[0020] In some embodiments, referring to Figure 2, this application also provides a three-phase control method for a converter, including a first-phase active transistor driving Vg1 and its first-phase energy storage inductor L1, a second-phase active transistor driving Vg2 and its second-phase energy storage inductor L2, and a third-phase active transistor driving Vg3 and its third-phase energy storage inductor L3. The control method includes a first load threshold and a second load threshold. The first load is defined as the load when it is equal to or lower than the first load threshold; the second load is defined as the load when it is between the first and second load thresholds; and the third load is defined as the load when it is higher than the second load threshold. As an example, this embodiment defines the first load as a 1 / 3 load, the second load as a 2 / 3 load, and the third load as the large output load.

[0021] When the first load is working, only the first phase operates. As shown in Figure 2, when the active transistor of the first phase drives Vg1 to output a high level, the energy storage inductor L1 of the first phase is energized, and the current increases linearly; when the active transistor of the first phase drives Vg1 to output a low level, the energy storage inductor L1 of the first phase is demagnetized, and the current decreases linearly.

[0022] When switching from the first load to the second load, as shown in Figure 2, the first phase's active transistor drives Vg1 to output a high level, energizing the first phase's energy storage inductor L1, and the current increases linearly. The second phase's active transistor drives Vg2 to output a high level, 180° out of phase with the first phase, energizing the second phase's energy storage inductor L2, and the current increases linearly. When the first and second phase's active transistors drive Vg1 and Vg2 to output low levels, the first and second phase's energy storage inductors L1 and L2 are demagnetized, and the current decreases linearly.

[0023] When switching from the second load to the third load, as shown in Figure 3, the first phase continues to operate. The active transistor of the first phase drives Vg1 to output a high level, energizing the energy storage inductor L1 of the first phase, and the current increases linearly. The active transistor of the second phase drives Vg2 to output a high level, 240° out of phase with the first phase, energizing the energy storage inductor L2 of the second phase, and the current increases linearly. The active transistor of the third phase drives Vg3 to output a high level, 120° out of phase with the first phase, energizing the energy storage inductor L3 of the third phase, and the current increases linearly. The active transistors of the first, second, and third phases drive Vg1, Vg2, and Vg3 to output low levels, demagnetizing the energy storage inductors L1, L2, and L3 of the first, second, and third phases, and the current decreases linearly.

[0024] In this embodiment, a first switch occurs when the first load transitions to the second load. The first switch is as follows: After the first load's single-phase operating cycle ends, the first phase continues operating. The active transistor of the first phase drives Vg1 to output a high level for a duration equal to half the single-phase drive's on-time. The cycle of the first phase also becomes half the single-phase operating cycle. After the first phase's first operating cycle ends, the active transistor of the second phase drives Vg2 to output a high level 180° out of phase with the first phase. The high level duration is also half the single-phase drive's on-time, and the cycle of the second phase also becomes half the single-phase operating cycle. At this point, both phases begin operating, thus completing the switch from the first load to the second load.

[0025] A second switching occurs when transitioning from the second load to the third load. The second switching is as follows: the first phase continues operating, with its active transistor driving Vg1 to output a high level. The duration of this high level is 2 / 3 of the single-phase drive conduction time in two-phase operation, and the period of the first phase also becomes 2 / 3 of the single-phase period in two-phase operation. After a short interval, the inductor in the second phase demagnetizes, and its active transistor drives Vg2 to output a high level 240° out of phase with the first phase. The duration of this high level is also 2 / 3 of the single-phase drive conduction time in two-phase operation, and the period of the second phase also becomes 2 / 3 of the single-phase period in two-phase operation. The active transistor in the third phase drives Vg3 to output a high level 120° out of phase with the first phase. The duration of this high level is also 2 / 3 of the single-phase drive conduction time in two-phase operation; the period of the second phase is 2 / 3 of the single-phase period in two-phase operation. At this point, all three phases are operating, thus completing the switching from the second load to the third load.

[0026] In this embodiment, the total conduction time remains unchanged when switching from single-phase to two-phase or to three-phase, and the frequency is increased several times by one-third of the single-phase conduction time of each phase, so that the total transmitted energy remains unchanged and the output is stable. At the same time, the switching is carried out at the beginning of a new cycle, which will not cause the current of the existing energy storage inductor to change suddenly, thus affecting the reliability of the system.

[0027] In some embodiments, this application provides a multiphase interleaving control method for a converter. The control method includes: setting several load thresholds and defining the load type according to the threshold range in which the working load is located; when the load operates in a first load range, it is a first load; when the load operates in a second load range, it is a second load; when the load operates in the (n-1)th load range, it is the (n-1)th load; when the load operates in the nth load range, it is the nth load, where n>3; when in the first load range, only one phase operates, the operating phase is the first phase, and the phases not operating are the second phase, the (n-1)th phase, and the... n phases, the first phase has a predetermined drive on-time and duty cycle; when the first load is used, only one phase works, the working phase is the first phase, and the phases that do not participate in the work are the second phase, the (n-1)th phase and the nth phase. The first phase has a predetermined drive on-time and duty cycle; when switching to the nth load, the switch is that the first phase continues to work, and the active tubes of each phase are driven to work in staggered phases according to a predetermined time. The drive on-time and duty cycle of each phase are reduced to 1 / n of the total on-time and duty cycle of the original single-phase work, and all n phases start working, thereby completing the multi-phase switching.

[0028] In this embodiment, whether it is single-phase switching, two-phase, three-phase or n-phase switching, the total conduction time remains unchanged, and the frequency is increased by a corresponding multiple, which is 1 / n of the single-phase conduction time of each phase, so that the total transmitted energy remains unchanged and the output is stable. At the same time, the switching is carried out at the beginning of a new cycle, which will not cause the current of the existing energy storage inductor to change suddenly, thus affecting the reliability of the system.

[0029] The above are merely some embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, and substitutions to the above embodiments within the scope of this application.

Claims

1. An interleaved control method for a two-phase switching converter, characterized in that, The control method includes: a first load threshold; a load equal to or lower than the first load threshold is considered low load, and a load higher than the first load threshold is considered high load; under low load, only one phase operates, the operating phase is the first phase, and the unoperated phase is the second phase; the first phase has a predetermined drive-on time and duty cycle; under high load, the first phase and the second phase operate simultaneously; a switching occurs when the load changes from low load to high load; the switching is as follows: the first phase continues to operate, its drive transistor is turned on, the drive-on time and duty cycle of the first phase are reduced to half of that under single-phase operation; after the single-phase duty cycle of the first phase ends, the drive transistor of the second phase is turned on, its drive phase is offset by 180° from the drive phase of the first phase, the drive-on time and duty cycle of the second phase are reduced to half of that under single-phase operation, and both phases begin to operate, thereby completing the switching from low load to high load.

2. An interleaved control method for a three-phase switching converter, characterized in that, The control method includes: a first load threshold and a second load threshold; a first load occurs when the load is equal to or lower than the first load threshold; a second load occurs when the load is between the first and second load thresholds; and a third load occurs when the load is higher than the second load threshold. Under the first load condition, only one phase operates, with the first phase operating and the second and third phases not operating. The first phase has a predetermined drive-on time and duty cycle. Upon transitioning from the first load to the second load condition, a first switch occurs, whereby the first phase continues to operate, driven by its active transistor, reducing its drive-on time and duty cycle to half that of single-phase operation. After the single-phase duty cycle of the first phase ends, the active transistor of the second phase is driven on, with its drive phase offset by 180° from the first phase, reducing its drive-on time and duty cycle to half that of single-phase operation. Both phases are then on. The system begins operation, thus completing the switch from the first load to the second load. A second switch occurs when transitioning from the second load to the third load. In this second switch, the first phase continues operation, its active transistor is turned on, and the on-time and operating cycle of the first phase are reduced to two-thirds of the time required for either the first or second phase to operate with two phases. After the two-phase operating cycle ends, the active transistor of the third phase is turned on, its driving phase offset by 120° from the driving phase of the first phase. The on-time and operating cycle of the third phase are reduced to two-thirds of the time required for either the first or second phase to operate with two phases. After the two-phase operating cycle ends, the active transistor of the second phase is turned on after a predetermined time, its driving phase offset by 240° from the driving phase of the first phase. The on-time and operating cycle of the second phase are reduced to two-thirds of the time required for either the first or second phase to operate with two phases. All three phases then begin operation, thus completing the switch from the second load to the third load.

3. A multiphase interleaved control method for a converter, characterized in that, The control method includes: setting several load thresholds and defining the load type according to the threshold range of the working load; when the load operates in the first load range, it is the first load; when the load operates in the second load range, it is the second load; when the load operates in the (n-1)th load range, it is the (n-1)th load; when the load operates in the nth load range, it is the nth load, where n > 3; when the first load is in operation, only one phase operates, the operating phase is the first phase, and the phases that do not participate in operation are the second phase, the (n-1)th phase, and the nth phase, and the first phase has a predetermined drive conduction time and working cycle; when switching to the nth load, the switch is that the first phase continues to operate, and the active tubes of each phase are driven to conduct in staggered phases according to a predetermined time, wherein the drive conduction time and working cycle of each phase are reduced to 1 / n of the total conduction time and working cycle of the original single-phase operation, and all n phases start to operate, thereby completing the multi-phase switching.

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